Field of the Invention
The invention lies in the printing technology field. More specifically, the invention pertains to a printing machine, in particular a sheet-fed printing machine with multiple processing stations that particularly include cylinders and drums and with a gear train formed with gear-wheels, which propel the cylinders and drums operationally, as well as a printing machine, a sheet-fed printing machine in particular, with at least one processing station that includes cylinders and drums and with one gear train consisting of intermeshing gear-wheels that propel the cylinders and drums operationally.
In the processing stations of a printing machine, in particular of a sheet-fed printing machine, alternating interference-torques in the gear train ensue. They are caused by cam-drives that drive the gear train, such as for example for the propulsion of a swing-gripper for the delivery of a resting sheet to a first cylinder. Those interference-torques can lead to oscillations and tooth-flank-changes, which can lead to mechanical wear and tear and above all to print-technological problems, namely to a deterioration of the print-quality, such as doubling or xe2x80x9cghostingxe2x80x9d.
To avoid the above-mentioned problems, German patent application DE 23 47 568 A1 provides for a swing-gripper-impulse of a printing-unit that a hydraulic control-device is pivoted at a swing-gripper-shaft, which is controlled by the machine with a closed-loop-control-system, whereby a torque-compensation with the swing-gripper is supposed to ensue. This is complex not only in terms of control but also in mechanical terms, if there are supposed to be variable nominal-actual-value-specifications through mechanical governors with speed-alternations.
German patent DE 41 01 823 C2 describes a gear train for the attainment of a secure tooth engagement in a gear train. The gear train has a bracing-gear-wheel separately positioned in the frame between two equidirectional turning gear-wheels, the position of which is adjustable in a positive manner.
Furthermore, U.S. Pat. No. 5,357,858 (European patent No. EP 613 775 B1) discloses a device, which touches two gear-wheels of a gear train that are combing together with each other. A first gear-wheel together with the propelling gear-wheel of the gear train is provided, where a second gear-wheel combs with the propelling gear-wheel of the gear train and where, coaxial to the first gear-wheel, a third gear-wheel is provided, that combs together with the second gear-wheel, and which is pre-stressed relative to the first gear-wheel. Such a configuration is very complex in mechanical terms.
Finally, U.S. Pat. No. 6,000,694 (German patent application DE 196 16 755) describes a drive system for an oscillating swing-gripper of a sheet-fed printing machine. There, a separate drive is provided for avoiding the above-mentioned torque-changes during normal operation. Due to safety reasons, for the case of a cessation of the additional controlled drive, there is provided a mechanical coupling of the swing-gripper together with the main-drive-phase-belt, though not effective during normal operation and which can also thereby not cause a torque-alternation in the main-drive-phase-belt. This solution too is complex and in particular relatively expensive.
It is accordingly an object of the invention to provide a printing machine which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which counteracts the influences of the appearing interference-torques of a gear train consisting of gear-wheels, which mesh with each other and to do that with simple and economical means.
With the foregoing and other objects in view there is provided, in accordance with the invention, a printing machine, in particular a sheet-fed printing machine, comprising:
a plurality of rollers and drums;
a gear train formed with a plurality of mutually meshing gear-wheels connected to and driving the cylinders and drums;
the gear-wheels of the gear train including first and second equidirectionally rotating gear-wheels each having a respective coupling position defined thereon; and
an elastic coupling articulated at the coupling positions, the elastic coupling transferring a periodically changing torque from the first gear-wheel to the second gear-wheel.
In accordance with an added feature of the invention, the coupling positions are defined in phase and at radially even positions of the first and second gear-wheels; or the coupling positions are defined out of phase and at radially even position of the first and second gear-wheels; or the coupling positions are defined in phase and at radially uneven positions of the first and second gear-wheels; or the coupling positions are defined out of phase and at radially uneven positions of the first and second gear-wheels.
In accordance with an additional feature of the invention, the elastic coupling is a resilient, i.e., springy, and absorbing coupling.
In accordance with another feature of the invention, the elastic coupling includes an elastomer part. In particular, the coupling may include a resilient and absorbing polymer.
In a particularly preferred embodiment, the elastic coupling includes a spring. Specifically, the elastic coupling may comprise a cylindrical housing and a coupling rod having an abutment-board guided within the cylindrical housing, and springs disposed between the cylindrical housing and the abutment-board.
In accordance with a further feature of the invention, the elastic coupling comprises a rigid coupling rod and a leaf spring connected to the rigid coupling rod. Further, the rigid coupling rod may be one of two rigid coupling sections connected by the leaf spring.
In accordance with again an added feature of the invention, there is provided a second elastic coupling connected between the first and second gear-wheels, the second elastic coupling operationally transferring a periodically changing torque from one to the other of the first and second gear-wheels. In accordance with a concomitant feature of the invention, the first and second couplings are disposed opposite one another and out of phase relative to one another.
With the above and other objects in view there is provided, in accordance with the invention, a printing machine, in particular a sheet-fed printing press, comprising:
at least one processing station including cylinders and drums;
at least one gear train formed with a plurality of mutually intermeshing gear-wheels connected to and driving the cylinders and drums; and
a crank assigned to one of the gear-wheels and configured to impress thereon a periodically changing torque.
In other words, the objects of the invention are achieved with a printing machine, of the type mentioned in the introductory text, in that a respective coupling position is assigned to the two equidirectional turning gear-wheels of the gear train and that an elastic coupling is provided at the coupling positions, which operationally transfers a torque periodically changing from one to the other of the two gear-wheels.
In a printing machine, in particular in a sheet-fed printing machine, with at least one processing station including the cylinders and drums, and with one gear train out of gear-wheels that mesh with each other and which operationally propel the cylinders and drums, it is provided in an alternative configuration, for a stationary pivoted elastic crank to be assigned to one of the gear-wheels, which impresses operationally a torque onto the gear-wheel that is periodically changing.
The instant invention thus proposes a purely mechanical solution without any electrical control or regulation and with a small number of parts.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a printing machine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.